encoding/json: Unmarshal of "null" string into map will panic after assignment

[vincepri]

https://play.golang.org/p/6GgCp-aY4Y

[bradfitz]

This is working as intended. You're telling it to turn &m into null, and it is, and then you're assigning to a nil map.

Unmarshal will return an error if you try to unmarshal an integer or boolean, but null and a JSON object can both unmarshal into a map.

[vincepri]

@bradfitz OK so I guess if that's the intended behavior, why I can still read from the map and it doesn't panic?

[bradfitz]

Because that's how the Go language works:

http://golang.org/ref/spec#Map_types

It says:

A nil map is equivalent to an empty map except that no elements may be added.

[vincepri]

Oh okay good to know :) Thanks Brad.

On Friday, April 10, 2015, Brad Fitzpatrick notifications@github.com
wrote:

Because that's how the Go language works:

http://golang.org/ref/spec#Map_types

It says A nil map is equivalent to an empty map except that no elements
may be added..

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